Intumescent furnace



Dec. 29, 1942.

H. F. MOORMAN INTUMESCENT FURNACE Filed May 19, 1941 INVENTOR M W w M FN m 5 H Patented Dec. 29, 1942 UNITED STATES PATENT OFFICE INTUMESCENTFURNACE Hesden F. Moorman, Los Angel, Calif. Application May 19, 1941,Serial No. 394,199

3 Claims.

This invention relates to and has for an object the provision of animproved means for intumescing or expanding certain minerals in the formof a light weight aggregate possessing a high insulation value, such asobsidian, perli-te, pitchare readily exfoliated by the mere applicationof heat, whereas such materials as perlite or other allied minerals,particularly of the obsidian family, are not effectively expanded forcommercial usage by heat alone but require the direct application offire for sustained periods in order that the material subsequent to mytreatment may be capable of commercial use, as for instance, as anelement of plaster applicable to walls of buildings, and as a componentof a sound deadening ,or insulating material.

The invention, therefore, comprehends the provision of an improved meanswhich includes a furnace in which the usual refractory lining isomitted, principally because the finest particles of material may adherethereto and become fused, and into which a flame from a high pressureburner is directed tangentially for providing a'maximum of turbulenceand in which the flame I traverses the interior of the furnace in aspiral or helical path. The material to be treated is introduced intothe furnace through a firing tube into which the flame from the burneris also introduced and the material is adapted to be held in suspensionwithin the furnace for sufficient periods of time to effect the completeintumescence of the particles before they are exhausted from the bottomof the furnace by suction to points of further treatment, such as forseparating the materials from the gases, or ultimate disposition.

An object, therefore, is to provide a. furnace having thecharacteristics herein named which may be effective either with orwithout the usual cyclone separating means common to other systems andis adapted for use in connection particles and for dispensing them asrequired for use.

Other objects include: means for regulating the feed of the material tothe firing tube; a primary means for regulating the volume of airadmitted to the firing tube; auxiliary means for in theaccompanying-drawing for carrying out the hereinabove named objects ofmy invention, subject to modification, within the scope of the appendedclaims, without departing from the spirit of'my invention.

In said drawing:

. Fig. 1 is a side elevation of an assembledap- 'paratus, shown partlyin section;

Fig. 2 is a sectional plan on line 2-2 of Fig. 1; and

Fig. 3 is a sectional elevation through the firing tube and the materialfeed hopper on line 3---3 of Fig. 1. g A

I Briefly described, my invention includes: a furnace A to which istangentially connected a firing tube B arranged for receiving a flamefroma high pressure burner C, a feed hopper D for holding a substantialquantityof material to be treated, a material feeding means E forregulating the volume of material fed from hopper D to the fur-- nace, aseparator F for separating the treated.

material from the products of combustion, a fan G associated with theseparator for exhausting the products of combustion, and a storagereceptacle I- I into which the treated material is deposited from theseparator and which isadapted to dispense the material into suitablebags, as at .I, or other forms of collecting receptacles.

The furnace A is preferably of cylindrical form with an inner wall I, anouter wall 2 and insulating material 3 between said walls, exceptpreferably for a small area directly opposite the inlet from the firingtube B. Said furnace has a top 4 with an opening 5 therein which isadapted to be covered by a plate or lid 6 and which is removable foraffording vision and access to the interior of the furnace at will. The

bottom ofthe furnace, as at 1, is of the conical form and may beintegral or separate from the with a suitable means for collecting thetreated 55 furna ody, s wn in Fi with a vertical outlet 8 connected witha horizontal section 9 of a discharge pipe carrying an air valve ordamper In in its end and connected with a riser pipe H which leads tothe separator F. The furnace is suitably supported upon a frame J.

The burner C is a high pressure type and.

adapted for use with either gas or oil and arranged for regulation ofthe volume of air for mixture with the fuel at a suitable point forproviding a maximum heat and efliciency, the burner not being a part ofmy invention. As shown in Fig. 1 the jet ll. of the burner is adjacentto the inlet of the firing tube B and said tube is, as shown in Fig. 2,disposed at a tangent to the inner wall of the furnace A so that whenthe flame from the burner is introduced into the furnace a substantialturbulence will be caused by the whirling of the flame while it istraversing the circular inner wall of the furnace so that when materialto be treated is fed through an inlet l3 into the firing tube thematerial will be held in suspension within the furnace for sustainedperiods of time in a disseminated state.

Feed hopper D is adapted to hold a substantial quantity of the materialwhich flows by gravity through an outlet l4 capable of being controlledby a suitable valve l5, and thence downwardly into and through a tube l6into a smaller hopper l1 attached to the upper end of inlet l3, fromwhich latter point the material is drawn into the furnace through firingtube B in accordance with requirements, as may be determined by thecapacity of the furnace.

As illustrated in Fig. 1, the flame and material to be treated isintroduced into the furnace through an orifice I8 and while the flametraverses a spiral downward path within the furnace as shown by thelines and arrows, the turbulence in the furnace tends to hold theparticles, large and small, of the material in'suspension for longenough periods to effect the complete intumescence of every particle,after which the particles are drawn downwardly by reason of the induceddraft in the pipe it caused by fan G.

Fan G creates suction in chamber I9 of separator F which is communicatedto pipe I l, section 9 and the interior of the furnace so that thetendency of the apparatus is to move the suspended particles through thefurnace, pipes 9 and II and separator F, but the turbulence in thefurnace is sumcient to hold the particles suspended in the furnace forsufficient periods of time to effect their intumescence before they areexhausted into section 9 and from said point to the separator F throughpipe ll.

The relative pressure from the flame of the burner and the suctioncreated by fan G is regulated either by the usual air valve on theburner or by the regulator III on section 9 of the outlet pipe, or byboth of such instrumentalities.

The material enters chamber IQ of the separator at a tangent through anorifice 20 and falls by gravity into the storage receptacle H through aneck 2| while the products of combustion are discharged upwardly throughan outlet 22 leading toa pipe 23 from which the gases are delivered toan axial opening in the fan G and are discharged from the fan through anoutlet 24. In this connection it may be noted that the section of theapparatus shown in Fig. 2 is also typical of the connection of pipe Hwith the separator F, and in some cases the burner C and firing tube Bmay be applied to the separator directly, or, the fan G may be appliedto the top of the furnace A and the outlet 2| be formed on or attachedto section 9 of the discharge means in lieu of the combined use of thetwo elements described. In the form shown, receptacle H has a dispensingoutlet 25 with a suitable valve 26 therein for regulating the dispensingof the treated material from the receptacle into a bag as at L orotherwise as may be convenient and desirable.

In connection with the furnace it is notable that when fir brick isemployed, as in some types of furnaces, the finest particles of materialare prone to cling to the refractory lining ancl fuse, hence I haveascertained that a stainless steel lining is most adaptable to preventsuch results.

In the operation of the furnace I have discovered that the kinds ofmaterial hereinbefore mentioned and which are granular or cellular andare not laminated are capable of intumescense at a temperature ofapproximately 1750 degrees Fahrenheit when the flame from the burner isdirectly applied to the granules, and I have also discovered that thesame temperature is ineffective for producing the desired results whenmerely heat of said temperature is applied to the material, While thesame temperature, more or less, may be effective for exfoliating mica,vermiculite and other laminated material, it requires more than mereheat and an actual application of flame to the particles of material,large or small, for accomplishing the results of this invention. To thisend, therefore, I have ascertained from experimentation, that an extremeturbulence must be maintained within the furnace, into which theparticles of materials are introduced in sufilcient volume, and theflame must be under a high pressure in order to hold the particles insuspension for periods of time requisite for eifecting their completeintumescence.

My system must also, and does provide means for the quick expulsion fromthe fire zone of the particles so that they may not become overhot anduseless commercially, i. e., they may become viscid and fusible whichmay also render them at times incapable of discharge from the fire zone.The material when treated in my apparatus is maintained in a closedcircuit from its point of entry to its point of ultimate disposition,and the deposition of a regulated volume of material into the firingtube and its conduct therethrough to the fire zone in which there isProvided a maximum of cyclonic turbulence, assures the suspension of theparticles throughout a sustained period sufiicient to effect completeintumescence and a resultant uniformity of the commercial product.

The several points of regulation render the apparatus capable ofadaptation to variations as between different materials, size of thefurnace and its capacity, altitude and other atmospheric conditions andother circumstances which may affect the product of the apparatus. Forinstance, the burner C has the usual fuel control valve 21 and aircontrol 28; the air regulator l0 applied to section 9 of pipe H forregulating admission of air to pipe II, and the fan G which may beadjusted to vary the suction which effects the removal of the treatedmaterial from the furnace and its separation from the products ofcombustion.

An apparatus of the character herein described lends itself readily toeconomy and efiiciency in operation in that several of the units may beattended by a single operator and the output will depend upon theparticular character and mesh of the material treated. after theapparatus has been once set for operation on a given kind of material.The fan G which is operatively associated with the separator F and thefurnace A creates sumcient draft through the furnace for effectingproper combustion and also for withdrawing the treated material andproducts of combustion from the furnace and for conveying the materialand products of combustion to the separator, at which point the treatedmaterial is: separated from the products of combustion and the latterare withdrawn from the separator while .the material is deposited in thereceptacle H.

It is to be particularly noted that not only is the material held insuspension in the furnace during a continuous state of turbulence, butthe material is at all times disseminated during the period of itssuspension, thereby permitting the direct attack on the separateparticles by the flame and from all sides and directions,simultaneously.

Hence, the means herein shown and described accomplishes the followingresults, viz., the provision of a continuous flow of air through theapparatus necessary for afiecting proper combustion; the creation of acyclonic turbulence which serves as a medium for supporting'the materialin disseminated suspension during treatment thereof; the continuousremoval of the material from the zone of treatment .byreason of thedraft; the utilization of the draft thus created for conveying thetreated mterial and the products of combustion to a suitable separatingapparatus; and finally, the S p ration of .the treated material from theproductsofcombustion and the deposit thereof in a suitable storage binor receptacle. -Moreover, the cyclonic turbulenee in the fire zone isnot only occasioned by the pressure applied to the flame from the burnerC, but also from the suction created in the apparatus by fan G, and.these two forces are relatiyely "adjustable as to intensity and volumefor retarding or speeding up the flow of the materials through thefurnace and theconse quent regulation of the len th or the treating'What I claim is:

1. An intumescentfumace comprising: a cylindrical furnace, a firing tubetangentially connected-therewith at the top of the furnace, a burner forprojecting a flame at high pressure intosaidtuizoeandfurnacesoastoeilfectaspiral traverse of the furnace by theflame, means for feeding finely divided intumescible material into saidtube at a point intermediate the burner and the inlet to the furnace sothat the particles thereof will be held in suspension while under thedirect attack of said flame, and means for discharging the treatedmaterial and the products of combustion.

'2. An intumescent furnace comprising: a furnace having a cylindricalbody, a firing tube tangentially'extended from the top thereof, a burnerfor projecting a flame at high pressure into said tube and furnace so asto effect a spiral traverse of the furnace by the flame, means connectedwith said tube and disposed between the burner and the furnace forfeeding finely divided intumescible material into said tube and thenceto the furnace so that the particles thereof will be held in suspensionwhile under the direct attack of .said flame, said furnace having aconical bottom, and an outlet in said bottom for discharging the'treatedmateria1 and the products of combustion, said outlet arrangedforconnection with a source of suction to eifect the discharge of the thefurnace so that the particles thereof will be held in suspension whileunder the' direct attack of said fiame,'said' furnace having a conicalbottom and an outlet in said bottom for discharging the treated materialand the products of com-.

'bustion. said outlet arranged for connection with a source of suctionto effect the discharge of the,

treated materials, and means for varying the discharge of the materialsto correspond to requirements of different materials, said lastmentioned means including a pipe connected with the out-- let of saidfurnace and arranged for connection with a source of suction, and adamper in said pipe for regulating air admitted thereto from theatmosphere, as described.

'nEsnEn F. MOORMAN.

